Study on High Temperature Completion Stimulation Fluid for Offshore Low Porosity Low Permeability Gas Field

Reservoir acidization and fracturing are two common stimulation measures used to enhance the productivity of low porosity low permeability wells. Offshore gas fields have less reservoir stimulation measures because of limitations in well completion method, job cost and safety. To improve the productivity of the high temperature low porosity low permeability gas field in Wenchang, a new completion stimulation fluid suitable for directional well and horizontal well has been developed. This stimulation fluid has the abilities of acidization, gel breaking, porosity improvement and anti-water blocking. Percent acid solubility of the stimulation fluid for formation solids is between 7.70% and 12.99%. This stimulation fluid is capable of in-depth acidizing and effectively reducing capillary pressure and enhancing cleanup of acidizing residues. Laboratory experimental results showed that the permeability of a rock sample contaminated by the stimulation fluid was resumed by more than 90%, and the permeability recovery of the rock sample was steady after second contamination by the stimulation fluid. Application of the stimulation fluid in Wenchang gas field gave birth to a production rate that is 1.7 times of the allocated production rate of each well, substantially releasing the productivity of the high temperature low porosity low permeability wells and providing a clue for the development of similar low permeability offshore gas fields.